As some were having difficulties with their PM systems I've upgraded the allowances from 50 to 100 stored PMs per box (in, out, sent etc.).
However I've also changed the system so that rather than preventing any new messages from getting through when the box is full, the system will now push the oldest ones out and replace them with the newest ones. If you have any important messages you want to hang on to you can create an additional folder for storing them in using the 'Rules, folders and settings' controls over on the left hand side of your PM screen.
PM me if you're still having any problems.
Service with a smiley.

Pete